/*********************************************************************************
 *Copyright:  (C) 2018 LingYun IoT System Studio
 *Author:  Guo Wenxue <guowenxue@gmail.com>
 *Copied by whut_zty <zhuty_cn@163.com>
 *Socket_server of sht_project.
 *Created in 20210113
 ********************************************************************************/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define LISTEN_PORT 9998
#define BACKLOG 13

int main(int argc, char **argv)
{
    int rv = -1;
    int listen_fd, client_fd = -1;
    struct sockaddr_in serv_addr;
    struct sockaddr_in cli_addr;
    socklen_t cliaddr_len;
    char buf[1024];

    listen_fd = socket(AF_INET, SOCK_STREAM, 0); //服务器端创建socket
    if (listen_fd < 0)
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -1;
    }
    printf("socket create fd[%d]\n", listen_fd); //输出创建的socket的fd号

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;//Ipv4
    serv_addr.sin_port = htons(LISTEN_PORT);//主机字节序转网络字节序(端口)
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);//主机字节序转网络字节序(地址)
    if (bind(listen_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)//绑定IP和端口号
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -2;
    }
    printf("socket[%d] bind on port[%d] for all IP address ok\n", listen_fd, LISTEN_PORT);

    listen(listen_fd, BACKLOG);//监听端口.BACKLOG:相应socket可以在内核里排队的最大连接个数

    while (1)
    {
        printf("\nStart waiting and accept new client connect...\n", listen_fd);
        client_fd = accept(listen_fd, (struct sockaddr *)&cli_addr, &cliaddr_len);//接收来自客户端的请求
        if (client_fd < 0)
        {
            printf("accept new socket failure: %s\n", strerror(errno));
            return -2;
        }
        printf("Accept new client[%s:%d] with fd [%d]\n", inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port), client_fd);

        memset(buf, 0, sizeof(buf));//为传来的数据开辟内存
        if ((rv = read(client_fd, buf, sizeof(buf))) < 0)
        {
            printf("Read data from client socket[%d] failure: %s\n", client_fd, strerror(errno));
            close(client_fd);
            continue;
        }
        else if (rv == 0)
        {
            printf("client socket[%d] disconnected\n", client_fd);
            close(client_fd);
            continue;
        }
        printf("read %d bytes data from client[%d] and echo it back: '%s'\n", rv, client_fd, buf);

        if (write(client_fd, buf, rv) < 0)
        {
            printf("Write %d bytes data back to client[%d] failure: %s\n", rv, client_fd, strerror(errno));
            close(client_fd);
        }

        sleep(1);
        close(client_fd);
    }
    close(listen_fd);
}

